This invention relates to a loading mechanism for a recording and/or reproducing apparatus for recording and/or reproducing information signals on or from a tape, such as a magnetic tape, accommodated within a tape cassette. More particularly, it relates to a recording and/or reproducing apparatus for recording and/or reproducing information signals using a tape cassette, which apparatus is provided with a pair of reel shafts each having an engaging member mounted with a bias towards the end of a supporting shaft, and a tape cassette transfer mechanism adapted for shifting the tape cassette inserted by way of the cassette inserting opening in a first direction normal to the reel shafts and guiding or loading the tape cassette for inserting and engaging the reel shafts with a pair of tape reels within the tape cassette.
The recording and/or reproducing apparatus in which information signals, such as audio or video signals, are recorded on a magnetic tape, which is wound between a pair of tape reels rotatably accommodated within the tape cassette, or the thus recorded information signals are reproduced from the tape, are in the current use. As one of such recording and/or reproducing apparatus, a digital audio tape recorder or DAT has been proposed, in which a tape cassette accommodating a magnetic tape as the recording medium is provided and digital audio signals are recorded on or reproduced from the magnetic tape in the tape cassette.
The tape cassette employed in the digital tape recorder is of a tightly sealable structure to protect the magnetic tape contained in the cassette body during storage or the like non-use period when the tape cassette is not attached in position within the digital audio tape recorder.
A tape cassette, generally indicated at 300 in FIGS. 1 and 2, is employed in the digital audio tape recorder. The tape cassette 300 has a main or cassette body 301 formed by a pair of upper and lower halves 301a, 301b abutted to each other, and a pair of tape reels 302, 303 are rotatably supported within the cassette body 301. A tape 304, such as a magnetic tape, is installed between these tape reels 302, 303. The tape 304 is extended outwardly of and on the front side or edge of the cassette body 301 by way of tape extraction openings 305, 306, formed at both front corners of the cassette body 301, so that the tape is placed from the tape reel 302 towards the other tape reel 303.
The reels 302, 303 are formed with reel shaft engaging openings 302a, 303a, into which are inserted a pair of reel shafts that are provided on the digital audio tape recorder for rotating the tape reels 302, 303. These engaging openings 302a, 303a are exposed to the outside by way of a pair reel shaft insertion openings 309, 310 formed in the bottom surface or wall of the cassette half 301b.
On the front side or edge of the cassette body 301, a lid 307 is mounted rotatably on a shaft or pin 308 to protect the tape 304 extended on the front surface of the cassette body 301 during the time the tape cassette 300 is not in use. This lid is rotationally biased in a lid closing direction for enclosing the tape 304 extended on the front side of the cassette body 301 by a spring, such as a torsion coil spring, placed about the shaft 308.
On the bottom surface of the cassette half 301b, a bottom cover 311 having a U-shaped cross section is slidably mounted for movement in the fore and aft direction, for closing the reel shaft insertion openings 309, 310 during non-use of the tape cassette 300 to prevent intrusion of dust and dirt into the cassette body 301. The bottom cover 311 is formed with a pair of insertion openings 312, 313, which, when the bottom cover 311 is moved towards the rear side or edge of the cassette body 301, are in register with the reel shaft insertion openings 309, 310 to permit the reel shafts on the digital audio tape recorder to extend into the interior of the main body 301. When the bottom cover 311 is moved towards the front edge or side of the cassette body 301, the insertion openings 312, 313 are offset relative to the reel shaft insertion openings 309, 310, and the bottom cover 311 extends over or covers a tape extracting section 314 provided on the front edge of the main body 301. The tape extracting section 314 has a cutout on the bottom front side of the main body 301 so that a tape guide member of the digital audio tape recorder may be inserted on the inner side of the tape 304 extended on the front side of the main body 301. This bottom cover 311 is biased by a spring, such as a torsion spring, in the direction for closing the reel shaft insertion openings 309, 310 and the tape extracting section 314.
The bottom cover 311 is engaged with a pair of outwardly biased locking pawls 315, 316, provided on the main body 301, and is formed with rear engaging openings 317, 318 and front engaging openings 319, 320 for locking the bottom cover 311 at the forward and rear positions, respectively. With the locking pawls 315, 316 engaged in the rear engaging openings 317, 318, the bottom cover 311 is locked at the position of closing the reel shaft insertion openings 309, 310 and the tape extracting section 314 and, with the locking pawls 315, 316 engaged with the front engaging openings 319, 320, the bottom cover 311 is locked at the position that opens the reel shaft insertion openings 309, 310 and the tape extracting section 314.
The rear engaging openings 317, 318 and the forward engaging openings 319, 320 are formed in a pair of recessed grooves 321, 322 provided on the bottom surface of the bottom cover 311 to extend in the fore and aft direction of the cassette body 301. Disengaging means, in the form of projections, which are formed on an upper surface of a bottom plate of a cassette transfer frame, not shown, of the digital audio tape recorder, are introduced into the recessed grooves 321, 322 for unlocking the locking pawls 315, 316 from the engaging openings 317, 318, 319, 320. That is, when the disengaging means in the form of projections are introduced into the recessed grooves 321, 322, the locking pawls 315, 316 are thrusted or urged towards the interior of the cassette body 301, so that the locking pawls 315, 316 are unlocked from the rear engaging openings 317, 318 or the forward engaging openings 319, 320 to unlock the bottom cover 311 from the cassette body 301.
The cassette body 301 is provided with positioning openings 323 for positioning the tape cassette 300 in the digital audio tape recorder when the tape cassette 300 is positioned within the tape recorder.
Meanwhile, in a digital audio tape recorder employing the above described tape cassette 300 as the recording medium, a cassette loading mechanism has been proposed, which is constructed to introduce the tape cassette 300 from the front side of the main body of the tape recorder, and which is known mainly as the front loading system. In the digital audio tape recorder provided with a cassette loading mechanism operating under a front loading system, the tape cassette 300 is introduced into a tape recorder housing 324, as shown in FIG. 3, via a cassette inserting opening 325 formed on the forward side of the tape recorder housing 324, with the lid 307 first, so as to be supported by a cassette holder or a cassette transfer frame, not shown, provided in the tape recorder housing 324. The tape cassette 300 is moved by the cassette holder or the cassette transfer frame in the horizontal direction, which is the direction normal to the rotary axes of the tape reels 302, 303, as shown by an arrow m in FIG. 3. During such movement in the horizontal direction, the unlocking means in the form of projections formed on the upper surface of the bottom plate of the cassette holder or the cassette transfer frame are introduced into the recessed grooves 321, 322 to disengage the locking pawls 315, 316 from the rear engaging openings 317, 318 of the bottom cover 311, and bottom cover actuating means, such as a projection, which are provided on the bottom plate of the cassette transfer frame or the cassette holder, then abutting on the forward edge of the bottom cover 311. When the tape cassette 300 is moved further in the direction shown by an arrow m in FIG. 3, the bottom cover 311 is moved in the opposite direction to the direction of movement of the main body 301 until the insertion openings 312, 313 in the bottom cover 311 are in register with the reel shaft insertion openings 309, 310, and the reel shaft engaging openings 302a, 303a facing to the outside of the main body of the cassette 301. The tape cassette is then shifted in the vertical direction, which is the direction of the rotary axes of the tape reels 302, 303 until the reel shafts 326 are inserted and engaged with the reel shaft engaging openings 302a, 303a. During such vertical movement, the lid 307 is engaged by lid actuating means, not shown, and thereby opened. Also, with such vertical movement, a tape guide, not shown, of the tape loading mechanism is introduced into the tape extracting section 314.
The tape guide is adapted to be moved horizontally within the casing 324, and is moved in the direction of the arrow m in FIG. 3 more forwardly than the tape extracting section 314 to extract the tape 304. When the tape guide is moved as far as a predetermined position, the tape 304 is guided along a predetermined tape running path so as to be taken up on a magnetic head drum 327 of the recording and/or reproducing head apparatus provided within the housing 324.
With the digital audio tape recorder having the above described front cassette loading system, the amount of the shift or displacement 1.sub.1 in the direction of the thickness of the cassette body 301, or in the direction shown by the arrow n in FIG. 3, by which the tape cassette 300, which is introduced via the cassette insertion opening 325 and is moved by the cassette loading mechanism, is selected to be larger than the thickness t of the cassette body 301.
The purpose of such arrangement is to prevent the main body 301 from contacting with a pair of reel shafts 326 or the tape guide, not shown, provided in the digital audio tape recorder housing, when the tape cassette is shifted in the horizontal direction as indicated by the arrow m in FIG. 3
Hence, the inner dimension of the housing along its height, that is, the distance 1.sub.2 between the cassette inserting openings 325 to the cassette attachment surface, need be at least twice the thickness t of the main body 301 and this thickness or distance 1.sub.2 creates difficulties in reducing the thickness of the overall apparatus.
There is also a risk that, with the tape cassette disposed in the recording or reproducing position in the housing, another tape cassette can be introduced by mistake from the cassette inserting opening 325.
Thus, there is a risk for the component parts of the digital audio tape recorder, such as the tape cassette or the loading mechanism, to be damaged or destroyed by such dual intrusion of the tape cassettes by mistake.